Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Muscle development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1990

Differential distribution of myosin isoforms among the myofibrils of individual developing muscle fibers.

Myosin was localized in situ in the posthatch chicken pectoralis using isoform-specific mAbs. The distribution among myofibrils was demonstrated by immunofluorescence and by immunogold EM. Fluorescein- or rhodamine-labeled antibody (12C5) specific for the head region (S1) of myosin was used as a marker to identify "embryonic" myosin. In longitudinal semithin frozen sections, a minority population of myofibrils stained intensely with 12C5. All other myofibrils in the same cell stained only weakly. Similarly, in Lowicryl-embedded ultrathin sections prepared for EM, a minority population reacted preferentially with gold-labeled 12C5. An antibody (5B4) specific for the rod portion of "neonatal" myosin reacted strongly with nearly all myofibrils, and this was evident by light and electron microscopy. A few of the fibrils that reacted strongly with 12C5 reacted weakly with 5B4. These observations demonstrate that an epitope reacting with 12C5 is more abundant in some myofibrils than in others within the same cell. Three categories of myofibrils can be identified by their relative proportions of embryonic and neonatal forms of myosin: in nearly all fibrils, a neonatal isoform predominates; in a minority population, embryonic and neonatal isoforms are both abundant; and in a few fibrils, an embryonic isoform predominates. It is concluded that there are distinct populations of myofibrils in which specific isoforms are segregated within an individual cell.

Aging↗
PubMed1990

Ornithine and S-adenosylmethionine decarboxylase activities and polyamine contents in developing muscle tissues and primary cultures of normal and polymyopathic hamsters.

Polyamine (putrescine, spermidine, and spermine) contents and ornithine (ODC) and S-adenosylmethionine (SAMDC) decarboxylase activities have been assessed in an age-dependent manner, in normal and polymyopathic (dystrophic) hamster skeletal muscle, heart, and tongue extract and in primary tongue myoblast and skin fibroblast cultures. At 2 weeks of age, polyamine contents were significantly elevated in all of the dystrophic hamster tissues studied when compared with their age-matched controls. The degree of this elevation decreased with the age of the animals, generally, to a level where no significant difference in polyamine contents could be noted between normal and dystrophic hamster tissues. ODC and SAMDC activities in whole tissue extracts were consistently highest in 2-week-old muscle extracts and also declined with age. However, no significant changes in ODC or SAMDC activities were evident in any of the dystrophic muscle tissues studied when compared with their age-matched controls. Polyamine contents in dystrophic hamster myoblast and fibroblast primary cultures were also during proliferation (1 and 2 days after the initial seeding) compared with cultures prepared from normal hamsters. ODC and SAMDC activities in primary myoblast and fibroblast cultures clearly reflected the rate of cell proliferation, with highest activities found in subconfluent cell cultures. However, in general, no significant dystrophic-related abnormality in ODC or SAMDC activity was evident in proliferating myoblast or fibroblast cultures. These results suggest that the elevated polyamine contents of dystrophic hamster tissues and primary cultures may be due to a deficiency in polyamine catabolism or transport.

Adenosylmethionine Decarboxylase↗
PubMed1976

Cyclic AMP in developing muscle of the rhesus monkey: effect of prostaglandin E.

Cyclic AMP levels, measured by a competitive protein-binding assay and by a prelabeling technique with adenine-14 C, were determined on fetal, infant, and adult heart, diaphragm, and skeletal muscle of the rhesus monkey (Macaca mulatta); the effect of PGE on cyclic AMP accumulation was also studied. The levels of cyclic AMP were higher in the 3 types of muscle from 150-day fetuses (91% of term) than in adult muscles and even higher at 78-100 days fetal age, and histological evidence indicated that by 65 days gestation, the majority of the rhesus skeletal muscle cells are in the myotube stage. These data agree with the observation in cell cultures that a decrease in cyclic AMP is correlated with fusion of myoblasts to form myotubes. PGE (2.8 MUM) stimulated cyclic AMP accumulation in all the fetal series, even in the earliest series (47% of term), as well as in all the adult series.

Age Factors↗
PubMed1986

Effects of 6-mercaptopurine on developing muscle cells in vitro.

Treating differentiating muscle cells in vitro with 6-MP has resulted in a number of myopathic changes, some of which resemble the changes seen in 6-MP-treated neonatal rats. 6-MP treatment was cytotoxic to myotubes, but not myoblasts. The degenerative changes observed in 6-MP-treated myotubes were quite similar to those described in the neonatal rats by Alleva and his colleagues (1981). The results of this investigation demonstrate that differentiating muscle grown in vitro can be used to investigate tissue-specific toxicity, although the mechanism by which 6-MP results in selective toxicity in myotubes remains to be elucidated.

Animals↗
PubMedDate not supplied

[Effect of vanadium compounds on the enzymic activity in sarcolemma of developing muscles].

Sodium metavanadate (10(-4)-10(-6) M) stimulates the activity of adenylate cyclase and decreases the activity of Na+, K+-ATRase and 5'-nucleotidase in the sarcolemma fraction of chicken skeletal muscles at the embryonal and postembryonal developmental stages. Under conditions of a combined action of vanadate and guanylic nucleotides on the adenylate cyclase activity their effects are found to be potentiated. Epinephrine in vitro removes an inhibitory influence of vanadate on Na+, K+-ATPase from the third week of twe embryonal period. The restoring effect of epinephrine is blocked by propranol--a beta-adrenoblocker.

5'-Nucleotidase↗
PubMed1992

Regulation of sarcoplasmic reticulum gene expression during cardiac and skeletal muscle development.

The expression of major sarcoplasmic reticulum proteins during cardiac and fast-twitch skeletal muscle development was examined using gene-specific probes. Through the use of S1 nuclease mapping, Northern blot, and RNA slot-blot analysis, sarcoplasmic reticulum proteins were shown to exhibit both narrow tissue specificity and plasticity in their expression during muscle development. In fast-twitch skeletal muscle, the cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin were detected at high levels in fetal stages but were gradually replaced by fast-twitch isoforms in adult muscle. In contrast, cardiac muscle expressed exclusively cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin at all stages. Both fast-twitch and slow-twitch skeletal muscle expressed the same skeletal muscle ryanodine receptor isoform, whereas cardiac muscle expressed a cardiac isoform. Phospholamban expression was restricted to cardiac and slow-twitch skeletal muscle and did not appear in developing fast-twitch skeletal muscle. During in vitro myogenesis of C2C12 cells, the mRNA transcripts encoding sarcoplasmic reticulum proteins were found to be coordinately induced in synchrony with that of contractile protein mRNA. The myogenic factor "myogenin" induced sarcoplasmic reticulum gene transcripts along with contractile protein mRNAs in nonmyogenic cells. These data suggest that the induction of both sarcoplasmic reticulum and contractile protein gene families is under the control of a common myogenic differentiation program.

Actins↗
PubMed1989

Nerve and muscle development in paralysé mutant mice.

Nerve and muscle development was studied in paralysé mutant mice. The mutant phenotype is first recognizable 6-7 days after birth (PN 6-PN 7) as cessation of muscle growth and weakness and incoordination of movement. Mutant animals die between 2 and 3 weeks of age. Muscle fibers from paralysé mutants had a unimodal distribution of diameters and normal numbers and distributions of acetylcholine receptors. The only structural abnormality seen was a reduced extracellular space within muscle fascicles. Total muscle choline acetyltransferase activity was reduced compared with that of control muscles, indicating that synaptic terminal development was impaired. Light and electron microscopy showed that polyneuronal innervation was retained in mutant endplates, and the normal process of withdrawal of redundant innervation did not occur. The paralysé muscles reacted to experimental denervation with an increase in extrajunctional acetylcholine receptor numbers. Intramuscular axons failed to become myelinated in mutant animals, although sciatic nerve axons were myelinated with a normal myelin thickness/axon diameter ratio. Nodes of Ranvier were elongated and myelin lamellae in the paranodal regions were poorly fused. Sciatic nerves in mutant animals retained the neonatal unimodal distribution of axon diameters, whereas in control animals it became bimodal by 2 weeks of age. Our results are not consistent with a previous suggestion that paralysé mutant muscle endplates are progressively denervated. We conclude that the major expression of the paralysé mutant phenotype is an arrest in development of both nerve and muscle during the first week after birth. The paralysé mutant gene most likely is involved in the general support of development of many or all body tissues from 1 week of age. We found no regression of any aspect of differentiation, once achieved.

Age Factors↗
PubMed1992

Contractile protein isoforms in muscle development.

The contractile proteins of skeletal muscle are often represented by families of very similar isoforms. Protein isoforms can result from the differential expression of multigene families or from multiple transcripts from a single gene via alternative splicing. In many cases the regulatory mechanisms that determine the accumulation of specific isoforms via alternative splicing or differential gene expression are being unraveled. However, the functional significance of expressing different proteins during muscle development remains a key issue that has not been resolved. It is widely believed that distinct isoforms within a family are uniquely adapted to muscles with different physiological properties, since separate isoform families are often coordinately regulated within functionally distinct muscle fiber types. It is also possible that different isoforms are functionally indistinguishable and represent an inherent genetic redundancy among critically important muscle proteins. The goal of this review is to assess the evidence that muscle proteins which exist as different isoforms in developing and mature skeletal and cardiac muscles are functionally unique. Since regulation of both transcription and alternative splicing within multigene families may also be an important factor determining the accumulation of specific protein isoforms, evidence that genetic regulation rather than protein coding information provides the functional basis of isoform diversity is also examined.

Actins↗
PubMed1978

Fast and slow myosin in developing muscle fibres.

Slow and fast isoenzymes of myosin coexist in all the fibres of a fast-twitch mammalian muscle during early development. They later become segregated into different populations of fibres. Slow myosin is most abundant when the speed of contraction of the muscle is slow and the fibres are multiply innervated; its synthesis in the majority of the fibres seems to be 'switched off' when the speed of contraction increases and the fibres become innervated by single motoneurones.

Animals↗
PubMed1991

Molecular analysis of protein assembly in muscle development.

The challenge presented by myofibril assembly in striated muscle is to understand the molecular mechanisms by which its protein components are arranged at each level of organization. Recent advances in the genetics and cell biology of muscle development have shown that in vivo assembly of the myofilaments requires a complex array of structural and associated proteins and that organization of whole sarcomeres occurs initially at the cell membrane. These studies have been complemented by in vitro analyses of the renaturation, polymerization, and three-dimensional structure of the purified proteins.

Actins↗
PubMed1986

Selective synthesis and degradation of slow skeletal myosin heavy chains in developing muscle fibers.

During fetal development of fast skeletal muscles in the rat, three types of cells could be identified using a monoclonal antibody to slow skeletal muscle myosin heavy chain. Presumptive type I cells stained positive for slow forms of skeletal myosin heavy chain and a previously described protein of an apparent molecular weight of 100 KD, whereas presumptive type 2B cells did not stain for either of these peptides. Presumptive type 2A cells, on the other hand, did not stain for slow isoform of 100-K protein, but did stain positive for slow skeletal myosin heavy chain. There was a progressive suppression or degradation of slow skeletal myosin heavy chain in presumptive type 2A cells during subsequent fetal development, so that it was almost undetectable in most animals at birth. Soleus, a slow muscle, however, did not show clear differentiation into presumptive type I and type 2 cells until 4 days after birth.

Animals↗
PubMed1986

Cerebral dysgeneses and their influence on fetal muscle development.

Abnormal suprasegmental influences of the brainstem and cerebellum on the developing motor unit during the histochemical stage of muscle development (20-28 weeks gestation) may alter the rate of maturation of striated muscle or may cause abnormal proportions and relative sizes of histochemical fibre types. Such aberrations without primary myopathic or denervative changes are commonly found in children with cerebral malformations, particularly associated with cerebellar hypoplasia. Upper motor neuron disease during embryonic life may explain histochemical alterations in some nonprogressive 'congenital myopathies' such as congenital muscle fibre-type disproportion, nemaline rod disease, and central core disease. Suprasegmental factors also may contribute to some aspects of the muscle pathology in the muscular dystrophies, especially the Fukuyama type of congenital muscular dystrophy regularly associated with cerebral dysgenesis. Fibre-type predominance or delayed histochemical differentiation thus may serve as a useful marker, in the muscle biopsy, of upper motor neuron disease. During the critical period of muscle development implicated, the corticospinal tract probably is of much less importance in muscle maturation than the multiple small bulbospinal pathways which also subserve motor control in nonmammalian vertebrates.

Brain↗